In the whole cohort, three patients died during the postoperative period. The mortality was 0.54 %. 551 patients over 15 years were identified, there were 37 (6.72 %) underweight (<18.5 kg/m2), 339 (61.52 %) normalweight (18.5–23.9 kg/m2), 146 (26.50 %) overweight (24–27.9 kg/m2), 29 (5.26 %) obese (≥28 kg/m2). 175(31.76 %) patients were overweight and obese. Patient baseline demographics and pathological variables were compared between the groups (Table 1). There was no statistically significant difference across the 4 BMI groups with respect to age, gender, ASA score, diabetes incidence, and abdominal operation history.
Short-term Perioperative Outcomes
The short perioperative outcomes were also shown in Table 1. The overall conversion rate was 13.1 %. Conversion rates for groups 1, 2, 3, and 4 were 13.5 % (n = 5), 11.5 % (n = 39), 13.0 % (n = 19), and 31.0 % (n = 9) respectively. Patients in the obese group were associated with a much higher conversion rate than the other three groups (p = 0.03). The total combined complications rate is 12.0 % in the present study, Complication for groups 1, 2, 3, and 4 were 22.86 % (n = 8), 12.68 % (n = 43), 8.22 % (n = 12), and 10.34 % (n = 3) respectively. Although there was a higher rate of complication in underweight group, overall complication rates did not differ significantly among the groups. No significant differences were observed in terms of operation duration, blood loss, blood transfusion, and postoperative LOS in the four groups. Obese patients had a longer postoperative LOS once converted to open approach (p = 0.002).
The complication rates according to the Clavien classification were reported in Table 1; they were 9.26 % for grade I to II and 2.72 % for grade III to IV. There was no grade V complication noted in any of the patients in this study. And no significant differences were observed in terms of the Clavien-Dindo classification among the four groups.
Reasons for conversion are shown in the Table 2. The top three reasons to conversion were unclear exposure, adhesions, and bleeding, by order of significance. There was a rare complication of diaphragm perforation that occurred, and the incidence rate was 1.39 %.
Surgical time and blood loss of different type of resection are listed in Table 3. Patients underwent right hemihepatectomy had the longest operative time and with the largest amount of bleeding. And longer time was needed in patients underwent left hemihepatectomy.
The types of complications were listed in the Table 4. Only the incidence of bile leakage was much higher in underweight group than that in other groups. There was no difference in the distribution of other complications in the four groups.
Independent factors for conversion and total complications were reported in Table 5. According to logistic analysis, conversion was strongly correlation to obesity and left hepatcetomy. Obesity and left hepatectomy were identified as a predictive factor of conversion [odd ratio (OR) = 5.06, 95 % confidence interval (CI) = 2.02–12.76, P = 0.001; OR = 3.4, 95 % CI = 1.36 ~ 11.45, P = 0.012 respectively]. Age, abdominal operation history, and left and right hepatectomy were identified as independent predictive factor for complications (OR = 1.03, 95 % CI = 1.01 ~ 1.54, P = 0.013; OR = 1.03, 95 % CI = 1.01 ~ 1.54, P = 0.013; OR = 4.39, 95 % CI = 1.62 ~ 11.89, P = 0.004; OR = 5.84, 95 % CI = 1.43 ~ 23.85, P = 0.014 respectively).
BMC Anesthesiol. 2016;16(29) © 2016 BioMed Central, Ltd.